Low impact gas spring

Abstract

A gas spring for providing a smooth and generally gradual load distribution between interrelated parts of a press has a casing defining at least in part a gas chamber. A housing is received at least in part in the casing. The housing has a through bore sized for receipt of the piston rod therein for reciprocation between extended and retracted positions. A piston retainer is attached for conjoint movement with the piston rod. An end of the housing flexes between a compressed position when the piston retainer abuts the housing as the piston rod moves toward its extended position and an uncompressed position when the piston retainer moves toward its retracted position and out of engagement with the housing.

Description

REFERENCE TO RELATED APPLICATION[0001]Applicant claims the benefit of provisional application, Ser. No. 60 / 602,777 filed Aug. 19, 2004.FIELD OF THE INVENTION[0002]This invention relates generally to gas springs, and more particularly to a gas spring constructed to reduce the impact force on a press during at least a portion of the stroke of the gas spring.BACKGROUND OF THE INVENTION[0003]Gas springs are well known and have been used in dies of presses for sheet metal stamping operations. Conventional gas springs have a gas chamber which receives a pressurized gas that provides a force on a piston and a piston rod of the gas spring to bias them to an extended position. The pressurized gas resists the movement of the piston and the piston rod from their extended position to a retracted position. Various housings and seals are provided in the gas spring to retain the piston and piston rod within a casing of the gas spring and to prevent leakage of the pressurized gas from the gas chamb...

AI Technical Summary

Benefits of technology

[0007]A gas spring incorporated in a machine, such as a press, for example, provides a smooth and generally gradual load distribution between interrelated parts of the press and gas spring, in use. The gas spring has a casing defining at least in part a gas chamber, a housing disposed at least partially in the casing, and a piston rod assembly received for reciprocation within the casing. The piston rod assembly has a piston retainer movable between a retracted position away from the housing and an extended position in abutment with the housing. The housing flexes between a compressed position when the piston retainer moves to its extended position and abuts the housing and an uncompressed position as the piston retainer moves toward its extended position and out of engagement with the housing. Accordingly, the housing of the gas spring contributes at least in part in providing the smooth and generally gradual load distribution between interrelated parts of the press.

[0008]Some potential objects, features and advantages of at least some presently preferred embodiments of this invention include providing a gas spring that requires a reduced force to initially displace a piston rod assembly from its extended position, reduces the impact force on a press when the press initially engages the gas spring, reduces the spike load on the press when the press releases from the gas spring, extends the useful life of the press, reduces the noise of the press and the gas spring in use, is durable, reliable, of relatively simple design, is of economical manufacture and assembly and has a long and useful life in use.

Problems solved by technology

In addition, since the mechanical drive mechanism of the press typically has already begun moving and accelerating the ram and the die half attached thereto before it begins to actuate and overcome the resistance produced by the gas springs, the initial impact or actuation of the gas springs creates an impulse or load spike of relatively high magnitude and short duration on the drive mechanism of the drive press.

The load spikes can cause an increase in the necessary press maintenance, thereby increasing the maintenance and repair costs of the press.

In some instances, the spike loads may damage the drive mechanism of the press, thereby decreasing the useful life of the press.

As such, the drive mechanism is subjected to further impulse or load spikes that can result in damage to the press or formed part, for example, by causing vibration.

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